Are Solid Fats or Oils Healthier? A Nutritional Deep Dive

January 13, 2026 •

3 min read

According to the American Heart Association, replacing saturated and trans fats with healthier unsaturated fats is a smart move for your heart. Navigating the kitchen's assortment of butters, shortenings, and liquid oils raises a key question: Are solid fats or oils healthier? Most of the time, the liquid option is the more heart-friendly choice.

Quick Summary

This guide explores the nutritional differences between solid fats and liquid oils, explaining their impact on heart health and offering practical advice for making healthier choices based on fat type and cooking method.

Key Points

Oils are generally healthier: Most liquid oils from plants and fish are rich in unsaturated fats, which are beneficial for heart health, unlike solid fats typically high in saturated fat.
Saturated fat raises 'bad' cholesterol: Solid fats like butter and lard increase LDL cholesterol, raising the risk of heart disease.
Trans fat is the most harmful fat: Industrially created trans fats are particularly dangerous for heart health and should be avoided entirely.
Choose the right oil for the right heat: Matching an oil's smoke point to your cooking method is important to prevent nutrient breakdown and the formation of harmful compounds.
Not all plant fats are the same: While most vegetable oils are healthier, tropical oils like coconut and palm are high in saturated fat and should be limited.
Dietary pattern is key: Your overall eating habits matter more than any single fat, so focus on replacing less healthy options with healthier alternatives as part of a balanced diet.

The Fundamental Difference: Saturated vs. Unsaturated Fats

At its core, the difference between a solid fat and a liquid oil comes down to its chemical structure, specifically the saturation of its fatty acid chains.

Solid Fats: Saturated and Trans Fats. Solid fats, like butter, lard, and shortening, contain a higher proportion of saturated fats, making them solid at room temperature. Certain plant-based fats, such as coconut and palm oils, are also high in saturated fat and remain solid. High consumption of saturated fats tends to increase levels of low-density lipoprotein (LDL) cholesterol, the "bad" cholesterol that contributes to heart disease. Trans fats, particularly industrially produced ones, are even more harmful. Created through partial hydrogenation, they increase LDL cholesterol while lowering high-density lipoprotein (HDL) or "good" cholesterol, posing a significant risk to cardiovascular health. It is widely recommended to avoid industrial trans fats entirely.
Liquid Oils: Unsaturated Fats. Oils derived from plants and fish are rich in unsaturated fats, which are liquid at room temperature. These fats are considered heart-healthy as they can help lower bad LDL cholesterol and, in some cases, raise good HDL cholesterol. There are two main types of unsaturated fats:
- Monounsaturated Fats: Found in high concentrations in olive, canola, and avocado oils.
- Polyunsaturated Fats: Include essential fatty acids like Omega-3s (found in flaxseed oil and oily fish) and Omega-6s (found in sunflower and corn oils).

Choosing Your Cooking Fat: Beyond Solid vs. Liquid

The simple rule of thumb is to choose liquid oils over solid fats for better heart health, but selecting the right oil also depends on your cooking method and specific needs.

Consider the Smoke Point

The smoke point is the temperature at which an oil begins to burn and produce smoke. When this happens, the oil can break down and release harmful free radicals. Matching your cooking method to the oil's smoke point is crucial.

High-Heat Cooking: For frying, searing, and roasting, choose oils with a high smoke point, such as refined avocado oil (~520°F), peanut oil (~450°F), or refined canola oil (~400°F).
Medium-Heat Cooking: Oils like extra-virgin olive oil (~375°F) are better suited for sautéing and baking.
No-Heat Applications: Delicate oils with low smoke points, such as flaxseed oil, should only be used in dressings or dips where they are not heated.

The Controversial Case of Tropical Oils

While most plant-based oils are high in healthy unsaturated fats, some tropical varieties are the exception. Coconut oil and palm oil are high in saturated fat and solid at room temperature, similar to animal-based fats. The health effects of coconut oil, in particular, are debated, as some studies suggest it may raise both good HDL and bad LDL cholesterol. However, when compared to other vegetable oils, many analyses show that coconut oil raises LDL cholesterol. Public health recommendations from organizations like the American Heart Association continue to advise limiting tropical oils.

Comparison of Common Fats and Oils


Feature	Healthier Liquid Oils	Less-Healthy Solid Fats	Trans Fats
Physical State (Room Temp)	Liquid	Solid	Solid (Industrially Produced)
Fatty Acid Profile	High in monounsaturated & polyunsaturated fats	High in saturated fats (Animal products, tropical oils)	Created from liquid oils via hydrogenation
Effect on Cholesterol	Can lower LDL and raise HDL	Increases LDL ("bad") cholesterol	Increases LDL and lowers HDL; highly detrimental
Common Examples	Olive oil, canola oil, avocado oil, sunflower oil	Butter, lard, shortening, coconut oil, palm oil	Margarines, packaged baked goods, fried foods
Health Recommendation	Emphasized as part of a heart-healthy diet	Limit intake to no more than 6% of daily calories	Avoid entirely; no known health benefits

Conclusion: Prioritize Unsaturated Fats

For most cooking and dietary uses, oils rich in unsaturated fats are the healthier choice, offering protective benefits for heart health. While all fats are calorie-dense and should be consumed in moderation, prioritizing liquid plant-based oils over solid animal fats and industrial trans fats is a key step toward improving your overall diet. Remember to also consider the smoke point to ensure you are cooking with the right fat for the job and not compromising its nutritional quality. Ultimately, a balanced approach focused on whole foods and smart fat choices is what matters most for long-term well-being.

For more guidance on healthy eating, you can visit the American Heart Association website for their dietary recommendations and tips on cooking with healthier fats: American Heart Association.

Frequently Asked Questions

Solid fats, like butter and shortening, contain a higher proportion of saturated fat, which can raise 'bad' LDL cholesterol levels. Liquid oils from plants and fish are rich in unsaturated fats, which help improve cholesterol levels and heart health.

Oils high in monounsaturated and polyunsaturated fats are the healthiest choices. Good examples include extra-virgin olive oil, canola oil, and avocado oil.

Trans fats, created through the partial hydrogenation of vegetable oils, both raise bad LDL cholesterol and lower good HDL cholesterol. This combination is particularly harmful and significantly increases the risk of heart attacks and stroke.

Yes. While plant-based, coconut and palm oils are high in saturated fat and behave similarly to animal fats. While there's conflicting research, many health organizations recommend limiting their intake due to their potential to raise LDL cholesterol.

The smoke point is the temperature at which an oil starts to burn. Cooking an oil past its smoke point can degrade its nutrients and release harmful free radicals. For high-heat cooking like frying, use high-smoke-point oils such as avocado oil. For dressings or light sautéing, lower-smoke-point oils like EVOO are fine.

For deep frying, it is best to use oils with a high smoke point, like avocado oil or refined peanut oil. However, it's worth noting that deep frying is generally not considered a healthy cooking method, regardless of the oil used.

Replace butter, shortening, and margarine with olive, canola, or avocado oil for cooking. Choose leaner cuts of meat, and substitute nuts, seeds, and avocados for animal fats in your diet.